In the design and manufacture of electronic systems, physical tolerances define the acceptable maximum deviation from the specified norm for a dimension of a component part or assembly. In some electronic systems, it is difficult to satisfy these tolerances and still produce good interconnectivity among the various components within the system. For example, consider an electronic system having a chassis and an electronic subassembly that enters into and couples to the chassis. This subassembly has an electrical connector configured to mate with an electrical connector of the chassis. For the electronic system to operate properly, the mating electrical connectors need to make minimal contact engagement and remain fully mated throughout the operation of the electronic system. Accordingly, tolerances affecting these connectors are determined such that the mating connectors are “bottomed out,” that is, fully engaged—one connector has penetrated the other connector as far as possible. This fully engaged condition presents the best opportunity for electrical contact between the electrical connectors.
To keep such connectors fully engaged, usually the subassembly is latched or locked within the chassis. Tolerances apply also to the placement of the latch mechanism on the subassembly and of any corresponding latch receptacle on the chassis. Considered in the determination of these latching mechanism tolerances are those of the connectors. For instance, there can be specified tolerances from the latch mechanism on the subassembly to the connector on the subassembly, from the connector on the subassembly to the connector on the chassis, and from the connector on the chassis to the internal latch receptacle on the chassis. Thus, proper latching between the subassembly and chassis involves complex, simultaneous satisfaction of numerous physical tolerances. If, for example, these tolerances indicate that the placement of the latch mechanism on the subassembly has a tolerance window of plus or minus 80 thousandths of an inch, then the chassis needs a latch receiving region measuring 160 thousandths of an inch wide gap to accommodate the various potential placements of the latch mechanism. Thus, a worst-case compliant system design can have almost 160 thousandths of an inch movement of the subassembly within the chassis. Movement of this magnitude can allow the latch mechanism to move during vibration and shock of the electronic system. Such movement can disengage the mating connectors and cause the electronic system to fail.
Further, mating electrical connectors have a preferred measure of “wipe”, that is, a minimum overlap between the mating connectors so that the act of joining the connectors operates to remove oxidants from the conductive elements, referred to as contacts, and thus improve electrical conductivity. The various tolerances can reduce this overlap to an unsatisfactory length. Thus, there is a need for a system capable of accommodating the various physical tolerances in an electronic system while providing robust mechanical connectivity and electrical conductivity between mating connectors.